// storage封装
const STORAGE_KEY='mall';
export default{
    //储存值
    setItem(key,value,module_name){
        if(module_name){
            let val=this.getItem(module_name);
            val[key]=value;
            this.setItem(module_name,val);
        }else{
            let val=this.getStorage();
            val[key]=value;
            window.sessionStorage.setItem(STORAGE_KEY,JSON.stringify(val));
        }
        
    },
    //获取某一个模块下的属性user下面的username
    getItem(key,module_name){
        if(module_name){
            let val=this.getItem(module_name);
            if(val){
                return val[key];
            }
        }
        return this.getStorage()[key];
    },
    getStorage(){
        return JSON.parse(window.sessionStorage.getItem(STORAGE_KEY)||'{}');

    },
    clear(key,module_name){
        let val=this.getStorage();
        if(module_name){
            delete val[module_name][key];
        }else{
            delete val[key];
        }
        window.sessionStorage.setItem(STORAGE_KEY,JSON.stringify(val));
    }
}